Hydraulic classifier



Aug. 9, 1955 Filed Dec. 9, 1955 W. J. FOX

HYDRAULIC CLASSIFIER 4 Sheets-Sheet l (dhm Q1 ATTORNEY ug- 9, 1955 w. J. Fox

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/TTORNEY United States Patent Office Patented Aug. 9, i955 HYDRAULIC CLASSIFIER William I. Fox, Old Greenwich, Conn., assignor to The Dorr Company, Stamford, Conn., a corporation of Delaware Application December 9, 1953, Serial No. 397,206 15 Claims. (Cl. 209-18) This invention relates to the wet or hydraulic classification treatment of pulp containing a range of particle sizes from fine to coarse, as exemplified by metallurgical pulps or pulps of wetaground ore, to effect the separation of the mixture of particles into a coarse and a fine fraction of sizes, these fractions herein to be simply termed the coarse across a weir. ln order to aid and control the separation,

the mixture of particle sizes while in transit through this pool may be kept mobilized by being subjected to the effect of controlled mechanical agitation, or subjected to the effect of a stream of auxiliary so-called hydraulic operating water up-owing through the pool at a controlled velocity; however, as contemplated by this invention, the mixture in the pool is subjected to the joint effects of both mechanical and hydraulic action, with the result that a desired coarse fraction above a certain mesh size will collect at the bottom of the pool to be withdrawn therefrom, while a corresponding fraction of fine sizes with its carrier water overflows from the pool, thus to afford superior means of separation control presently to be set forth.

It is among the basic problems in such wet classification or separation treatment that there be effected as sharp a separation as possible between the oversize and the undersize or else between the underow sizes and the overflow sizes; thus the aim is to conduct the classification treatment in such a manner or with such type of V` apparatus that each of the two fractions be obtained as free as possible from stray sizes of the other fraction.

Another basic problem in such wet classification treatment or apparatus is that of providing control means whereby the point of separation or fractionation or cut between the two groups of sizes, the oversize and the undersize can be readily established and accurately adjusted. For example, if the feed be of a run containing particle sizes ranging, say, from 28 to 200 mesh, then it should be possible, for example, to make a clean split at say, 100 mesh, yet it should be possible to readily shift the cut to, say, 48 mesh. This calls for providing simple and effective means for so adjusting or shifting the cut while deriving the respective size fractions clean, that is with a minimum of stray sizes admixed thereto. For example, the importance of producing a clean coarse fraction is apparent where the classification apparatus operates in closed circuit with a wet grinding mill, the mill to receive coarse fraction particles for regrinding, and where the admixture of an appreciable amount of undersize or stray sizes would burden the circulating load i through the mill and would accordingly reduce its efficiency as well as that of the circuit as a whole.

Moreover, there is the general problem that such an apparatus should be capable of handling effectively a feed slurry containing a relatively wide range of particles of extreme sizes, that is, from relatively very fine to relatively very coarse.

Also there is to be considered in the operation of such classification treatment and apparatus the degree of dilution of the feed pulp, since it is desirable to produce a separation which remains substantially stable in spite of possible variations in the degree of feed dilution; another aspect lies in the fact that it may be desirable to derive the overflow of fines at the highest possible density, there being the difficulty that a high rate of hydraulic water required might run counter to the goal of attaining the desired degree of overfiow density.

The invention provides improvements over the wet classification machine employing the joint or compound effect of mechanical and hydraulic classifying action shown in the patent to W. C. Weber, No. 2,302,588, which produces a sharp cut easily and accurately controllable, and which is operable with minimum of hydraulic operating water, capable of absorbing appreciable changes in the dilution of the feed pulp substantially without `affecting the cut itself, even though capable of producing the overflowing undersize fraction at relatively great density, and of handling a feed pulp containing a wide range of particle sizes from fine to coarse.

It is among the objects of the present invention to produce a machine possessing at least the operational characteristics and capabilities of the machine in the aforementioned patent, yet to be simpler of construction, lighter in weight, cheaper to build, as well as simpler to maintain, simpler to overhaul and simpler to service, and last but not least, which is more compact and which lends itself to a variety of structural modifications whereby it is conveniently and compactly adaptable for structural integration in a treatment system such as closed-circuit grinding. The significance of these objects will appear more precisely from the following outline of the machine shown in that patent. In that machine, the pulp is fed to a significantly shallow pool the bottom of which is formed by a horizontal circular false bottom in the form of a perforated plate usually termed a constriction plate. A hydraulic supply chamber is associated with the under side of the constriction plate unitary therewith and has hydraulic operating water fed thereto continuously in order that such auxiliary water may continuously rise in the pool through and upwardly from the constriction plate at a controllable rate, thus helping to maintain the par ticles in the pool in a mobilized state. Moreover, this hydraulic chamber with its constriction plate is mounted for oscillatory movement about a vertical axis by means of a hollow vertical column rising from the center of the constriction plate and suspended from an overhead bearing structure which carries drive mechanism for imparting the oscillatory movement through the column to the constriction plate and its associated hydraulic supply chamber. The slurry or pulp is fed to a central annular feed well surrounding the column, and under normal operating conditions the pulp in the pool is subjected to the joint effect of the oscillatory motion of the constriction plate and of the hydraulic water rising therethrough. A uniform distribution of hydraulic water over the entire bottom of the pool is thus obtained not only by reason of the fact that the water is being introduced by the great many holes in the constriction plate, but also because these holes are constantly being oscillated incident to the oscillatory motion of the constriction plate.

The classifier pool is furthermore defined by a cylindrical stationary boundary wall the top edge of which constitutes an overflow weir for discharging the undersize fraction of the pulp. This cylindrical boundary wall of the pool is concentric with the constriction plate although of a somewhat smaller diameter so that it is spaced slightly inwardly from the periphery of the constriction plate, yet also spaced upwardly from the marginal portion of the constriction plate. Thus, the constriction plate may oscillate beneath the stationary boundary wall, with the vertical distance between this wall and the constriction plate constituting an annular sands passage or solids transfer passageway leading outwardly from the pool bottom to allow for the outward migration and removal of the oversize fraction of the pulp from the pool. Importantly, along the periphery itself of the constriction plate there is provided what is herein termed a submerged sands discharge weir over which spill the sands or coarse fraction particles down into a receiving chamber which in turn surrounds the constriction plate. The sands discharge weir rises to a level at least somewhat higher than the sands passage, so that thereby there is maintained an annular sealing column of sands in transit between the passageway and the weir.

The annular space between the constriction plate and the surrounding receiving chamber is covered and closed by a top portion of the receiving chamber, which top portion in fact supports the cylindrical boundary wall of the pool by being rigidly connected therewith.

A body or column of clear water maintained in the sands receiving chamber defined by a clear water overfiow weir of adjustable height balances the column of pulp or mobilized particles in the pool, and this balance represents a hydraulic equilibrium condition in the machine, whereby the separation or cut is readily controllable, namely, as by adjustment of the height of the clear water overow weir.

The coarse fraction particles upon the oscillatory constriction plate will move or migrate outwardly, radially in all directions towards and through the sands discharge passage and over the submerged sands discharge weir which surrounds the passage, and into the lsurrounding sands receiving chamber whence they can be removed into emergence from a body of clear water as by any suitable conventional elevating means or by controlled spigot discharge means.

Thus, it is among the more specific objects of this invention to provide a machine which, while possessing at least the operating features and advantages of a machine such as above outlined, is simpler, lighter and cheaper of construction, with a substantial reduction of the oscillatory, or moving, masses, which is more compact and which is more readily and more compactly adaptable to environmental structural conditions, for example in what is known as metallurgical operations as closed circuit grinding systems.

The objects of this invention are attained by a machine which is functionally similar to one which is disclosed in the application to Harold B. Coulter, Serial No. 397,205, filed December 9, 1953, concurrently herewith in that it provides a classifying pool where the feed pulp enters at a point spaced from the point of fines overfiow discharge and from the point of sands underflow discharge. For example, the pulp may pass in a longitudinal direction from end to end through the pool undergoing classification, the underflow discharge being by way of a sands passage at the bottom of the pool and through a connecting sands column outside this passage. The desired kind of classification of the pulp in the pool is effected by the conjoint action of hydraulic water being introduced in substantially uniform distribution at the bottom of the pool and of horizontal longitudinal back-and-forth or vibratory movement of the bottom face of the pool. This movement is such as to provide suicient acceleration and deceleration within its vibratory cycle, to continuously induce and maintain an intensified degree of relative movement between the surface and the strata of oversize particles supported thereby. The cut between the two fractions is controllable by way of adjusting a static hydraulic counter-pressure effective at the sands discharge passage. One mode of so controlling the hydraulic counter-pressure is by way of a water column superimposed upon the sands column and defined by an adjustable clear water overflow at the super-elevation level. That is to say, the oversize particles from the sands column may be allowed to spill into a clear water chamber thence to be removed upwardly by suitable elevating mechanism, or downwardly by a .suitably controlled spigot discharge valve. The fines fraction discharges by overflowing from the classifier pool.

In distinction from the apparatus of the above mentioned application, this invention provides a machine so organized that the classifier pool is held in and by a stationary solid tank structure in which the classifier bath is defined by a horizontal bottom face, a pair of side wall faces, and a transverse wall face at each end, but where provision is made for only the bottom face to be vibratable horizontally in a substantially rectilinear direction.

More precisely, there is provided a solid tank structure having side walls, end walls, and a solid bottom of its own, to which tank structure there is added an auxiliary vibratable bottom element guidedly mounted within the tank structure to perform horizontally vibrating movenient therein. However, provision is made to have sealing means effective in a manner to prevent solids from the classifier bath from entering obstructively into the space below the vibratory bottom, namely into the space between the vibratory bottom and the solid bottom of the tank structure.

One embodiment comprises a stationary rectangular tank structure to hold the classifier pool which tank strueture has solid side walls, solid end walls, and a solid bottom, a feed inlet for pulp to be classified, an overflow for the fines fraction, and at the bottom it has a discharge passage for the coarse solids fraction, and means for delivering the coarse fraction at a controlled rate therefrom. Within this tank is mounted a vibratory bottom spaced from the solid bottom and in horizontally guided relationship therewith, and representing the bottom face that is in direct contact with the classifier pool. Horizontal and substantially rectilinear reciprocatory movement is imparted to this vibratory bottom by an external vibrating device actuating the vibratory bottom as through suitable diaphragm means provided in and upon a suitable wall portion of the tank. This embodiment provides a filler material that is resiliently deformable as well as resiliently compressible to be sealingly interposed between the movable and the solid bottom, to prevent the entry of solids into the space below the auxiliary bottom plate.

Control of the delivery rate for the coarse fraction solids may be effected in various ways one of which provides for the solids from the discharge passage to spill over a submerged discharge weir somewhat higher than the passage into a receiving pocket which communicates with a clear water column the height of which is determined by an adjustable overflow. The height of this overflow above the top level of the classifier pool determines the degree of super-elevation which in turn is what controls the cut at which the separation of the fractions is to be made. An overhead supply system provides for introducing hydraulic operating water distributively into the bottom strata of the classifier pool, while the fines or undersize fraction discharges through overow from the pool.

According to one feature, the movement of the reciprocating bottom is guided within the stationary tank by means of a pair of substantially vertical links at each side, each link having its lower end pivotally connected with the bottom and its upper end pivotally connected with the tank.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the metes and bounds of the claims, or of forms that are their functional as well as conjointly cooperative equivalents, are therefore intended to be embraced by those claims.

Figure 1 is a longitudinal vertical sectional view in diagrammatic fashion of one embodiment of the classifier apparatus.

Figure 2 is a View similar to that of Figure l, although structurally more fully implemented.

Figure 3 is a plan view of the classifier apparatus taken on line 3 3 of Figure 2.

Figure 4 is a vertical cross sectional detail View taken on line 44 of Figure 2, of the means for actuating the auxiliary bottom plate.

` Figure 5 is a vertical sectional view taken on line 5 5 of Figure 4. t

Figure 6 is a vertical cross sectional view of the classifier apparatus, taken on line 6-6 of Figure 2, showing a cross section of the classifier tank proper as well as of the fines overflow discharge means.

Figure 7 is a vertical cross sectional view of the classifier apparatus, taken on line 77 of Figure 2, showing a cross section of the sands receiving chamber.

Figure 8 is a vertical cross section of the classifier apparatus, taken on line 8-8 of Figure 2, showing the arrangement of suspension links for supporting the auxiliary bottom.

The diagrammatic view of Figure 1 of the classifier apparatus comprises a stationary classifier tank 10 proper containing a classifier pool 11 and having feed pulp supplied at one end thereof as -indicated by a supply chute 12, and having at the other end an overflow 13 provided with a receiving launder 14 for discharging the fines fraction from the top zone of the pool and further having a discharge passage 15 at the bottom of the discharge end, through which passes coarse fraction material 16 from the bottom zone of the pool.

The tank 10 has side walls 16 and 17, a front end wall 18, a rear end wall 19, and a bottom 20. At its rear or discharge end the tank is connected with a sands receiving chamber 21 which comprises a receiving pocket 22 and a neck portion 23. From the bottom of the passage 15 extends a shelf 24 outwardly into the neck portion 23 and from the outer edge of this shelf 24 rises a submerged sands discharge weir 25 to a point slightly higher than the upper edge 15a of passage 15.

The sands receiving chamber 21 is provided with an overflow pipe 26 the height of which determines the level L2 of liquid in the chamber 21, and it also determines the superelevation H1 of level L2 above the level L1 of the pool 11. Otherwise expressed, the superelevation H1 presents itself as the differential between the height of the clear water column H2 in the receiving chamber 21, and the height H3 of the pulp column in the pool 11, the heights of both columns H2 and H3 being measured as from the upper edge 15a of passage 15.

A sands receiving mechanism is provided in the receiv ing chamber 21 for elevating the coarse fraction material from the pocket 22 to a point of emergence for delivery from the chamber, such mechanism here being shown in the form of an endless pocket type elevator 27.

Within the tank 10 there is provided an auxiliary bottom 28 spaced from the solid tank bottom 20 and mounted to perform horizontal reciprocatory or vibratory movement as indicated by double arrow A1. Sealing means are provided to be effective between the auxiliary bottom and the surrounding tank bottom portion, whereby pulp material is prevented or discouraged from entering into the space between the auxiliary bottom 28 and the solid bottom 20, such sealing means here being shown in the form of a pad of resiliently deformable material such as sponge rubber. A Ctuating mechanism for the auxiliary bottom 28 is shown to be in the form of a vibrating mechanism 29 comprising a vibrating unit 30 proper supported by a suspension orlink member- 31. The vibrating unit 30 is shown to comprise a pair of eccentrically weighted shafts 32 and 33 geared up with one another and driven as by a motor 34 through an endless drive transmitting element or belt 35. The vibrating unit 30 imparts to the auxiliary bottom 28 horizontally reciprocating or vibrating forces indicated by arrow A2, thereby actuating the auxiliary bottom 2,8 through a stem 36 rigidly connecting the vibrating unit 30 with the auxiliary bottom 28. That is to say, the stem 36 extends through a diaphragm 37 provided in and constituting part of the end wall 18.

Means for distributively introducing hydraulic operating water into the bottom zone of the pool 1 1 are here indicated by way of a stationary horizontal jet emitting pipe 38 disposed in the bottom Zone of the pool, and supplied with pressure water through a. vertical feeder pipe 39 provided with a control valve 40. The horizontal pipe 38 has jet emitting orifices suitably disposed and spaced along the length of the pipe as is indicated by a row of jets 41 directed towards the bottom member 28. A practical and operatively suitable arrangement of a set of such jet emitting pipes and of the jets relative to the top face of the bottom member 28 will be described more fully in connection with the more detailed construction described below in reference to Figures 2 to 7.

Suffice it to say here that the arrangement of the jet emitting pipes be such that the combined effect of the jets will produce what is in effect a flow of operating water rising from the bottom member in substantially uniform distribution across the area thereof.

According to Figures 2-7, a construction of the classifier apparatus structurally more fully implemented com-V prises a stationary classifier tank 42 containing the classi fier pool P, which tank has a pair of side Walls 43 and 44, a front end wall 45, a rear end wall 46, and a bottom 47. Pulp feed to the tank is indicated by a feed chute 48 at the front end of the tank. The rear or discharge end of the tank has laterally disposed an overflow weir 49 determining the level L1 of the pool 43, for discharging the nes fraction from the top zone of the pool into a receiving trough 49a which has a discharge connection 49h. At the bottom of the tank at the discharge end thereof there is provided a sands discharge passage 50 through which passes the coarse fraction material `at a controlled rate from the bottom zone of the p'ool. A submerged sands discharge weir S1 is functionally associated with the passage 50 and is slightly higher than the top edge Sil of that passage, the weir 51 being outwardly spaced from the passage so that the coarse fraction material migrating through the passage will build up thereat to a point of spilling across the Weir 51 and into a receiving chamber 52. 'A

The receiving chamber 52 has a neck 53 whereby it isy connected to the end of the tank 42 as is indicated by a flange connection 54. The receiving chamber 52 com.- prises a sands receiving pocket 5'5 into which extends an endless bucket type elevating mechanism 56 for raising the coarse fraction material from the receiving chamber 52 or pocket 55 to a point of emergence and discharge. This receiving chamber 52 is provided with an overflow pipe 57 the top end of which determines the overflow level L2 of the liquid column maintained in the receiving chamber 52. The receiving chamber 52 comprises a main section 52a and a side chamber or lateral extension 52h. The main section comprises an outer transverse wall 58, an inner transverse wall 59, a bottom wall 60 which is curved in conformity with a lower endof the bucket elevator 56, and a pair of side walls 61 and 62. The lateral extension or side chamber 52b of the receiving chamber communicates with the main section 52EL by Vway of a passage 63, this extension chamber 52b comprising an outer wall portion 64, and opposite to it the wall portion 62, an outer lateral wall portion 65, an inner lateral wall portion 66, and an inclined bottom portion 67. The aforementioned overflow pipe 57 is disposed within the side chamber 52b and is intersected by the sloping bottom 67 thereof. It is noted that the submerged discharge weir 51 is disposed within the neck 53 of the receiving chamber and close enough to the rising side of the bucket elevator so that a quantity of the coarse fraction solids may be intercepted directly by the buckets or troughs '36a of the elevator as they spill from the submerged weir 51.

The tank 42 has a supporting frame structure indicated by a pair of corner posts 68 and 69 at one side and a pair of corner posts 70 and 71 at the other side of the tank, transverse member 72 between posts 63 and 70 respectively and transverse member 73 between posts 69 and 71, and diagonal bracing indicated at 74 and 75 between the posts at each side of the tank. The receiving chamber 52 is shown to be rigidly connected to tank 42 and rests upon a footing 76.

Within the tank 42 there is provided an auxiliary bottom member 77 mounted to perform reciprocatory or vibratory movement horizontally in the direction indicated by arrow As. That is, a pair of substantially vertical parallel link members or their equivalents are provided at each side of the bottom member 77, the lower ends of the links being operatively connected to the bottom member and their upper ends operatively connected with and supported by the top end portion of the tank walls. Thus, one pair of links 88 and 89 is disposed adjacent to and associated with the tank side wall 43, the other pair of links 90 and 91 being disposed adjacent to and associated with the tank side wall 44. The lower ends of the links are shown pivotally connected with respective side portions of the bottom member as at 88a, 89a, 90a, and 91@L respectively. The top ends of links 88 and 90 have a common transverse shaft 92 which in turn is rotatably mounted or journalled as at 92aL and 92b upon the top of respective side walls 43 and 44; the top ends of links 89 and 91 have a common transverse shaft 93 which in turn is rotatably mounted or journalled as at 93a and 93b upon respective side walls 43 and 44.

The auxiliary bottom plate member 77 is spaced from the solid tank bottom 47 a suitable distance d2 and sealing means are provided to be effective between the auxiliary bottom member 77 and tank bottom 47 to prevent or discourage the entry of pulp material into the space between them, such sealing effect being indicated by a pad or filler 94 of deformable and resiliently compressible ma- 7 terial such as sponge rubber.

Reciprocatory or vibratory motion in a horizontal direction is imparted to the auxiliary bottom plate member 77 by means of a vibrating device 95 which comprises a vibrating unit 96 proper supported by the lower end of a link member or suspension member 97 having an anchoring point 98. Vibrating unit 96 is driven by a motor 99 as through an endless drive transmitting element or belt 100 with the result that horizontally directed reciprocatory free forces indicated by arrow A4 are imparted to the auxiliary bottom plate 77 through a pair of horizontal stems 101 and 102 extending parallel to one another and here Shown to constitute a substantially rigid operating connection between the vibrating unit 96 and the auxiliary bottom plate 77 namely in such a manner that vibrating unit 96 together with the bottom plate 77 constitute a unitary vibratory mass. More precisely, the vibrating unit 96 has at each end thereof a bracket plate 96*ab and 96b respectively, and a bracket member 103 U-shaped in plan view and rigidly connecting the bracket plates 96a and 96h.

lThe stems 101 and 102 have their inner ends 101a and 102a welded to the auxiliary bottom plate 77 and their outer ends 101b and 102)@ iixed to the U-shaped bracket 103; that is to say, the outer ends 101b and 102D of the stems comprise a threaded end portion of the length l 8 extending through the bracket member 103 at right angles thereto, each of the stems 101 and 102 being held tixedly connected to the bracket member 103 as by a pair of lock nuts, namely a pair of lock nuts 104 and 105 for stern 101, and a pair of lock nuts 106 and 107 for stem 102. Each of the stems 101 and 102 extends through the end wall 45 of the clarifier tank by way of a neck 108 having a flange portion 108 at its outer end. A cup-shaped or bulbous diaphragm 109 surrounds each of the stems to provide sealing relationship between the stem and the end wall 45. The diaphragm 109 is here shown to comprise a cupshaped or bulbous body portion 1093, an inner wide end portion defined by a flange portion 109, and an outer narrow portion 109c hugging the respective stems. The wide Z- end flange portion 109b is secured to flange 108a of neck 1015 as by means of a holding ring 110 and bolts 110g. The narrow end portion 109C of the diaphragm member is held tight to and around the respective stem as by means of a clamping device 111.

Hydraulic operating water is introduced distributively at the bottom of the clarifier tank, that is in the bottom zone of the clarifier pool, by means of horizontal jet emitting pipes 112 and 113 spaced a suitable distance dz from the auxiliary bottom 77. Each of these jet emitting pipes is shown to have a pair of vertical feeder pipes, the horizontal pipe 112 having a pair of feeder pipes 112a and 1120, the horizontal pipe 113 having a pair of feeder pipes 113a and 1131. The vertical feeder pipes 112a and 112b are interconnected by a subheader 114, while the feeder pipes 113a and 113b are interconnected by a subheader 115, the subheader 114 and 115 being interconnected by a main header 116 provided with a supply pipe 1162- having a control valve (not shown). rhis system of piping for distributively supplying hydraulic operating water to the bottom of the classifier pool is so mounted upon and supported by the classifier tank that it can be raised from the tank for inspection of the horizontal jet emitting pipes 112 and 113 and of the jet emitting orices therein.

Each horizontal pipe has along each side thereof a row of jet orifices indicated by jets I which jets are spaced from one another a suitable distance s, the jets being inclined towards the bottom under a suitable angle w" below the horizontal. The distance between pipes 112 and 113 is t, while the distance between each of these pipes and the respective sidewalls of the classifier tank is designated as u, with u being shown substantially equal to 1/2 t, all as specified more precisely in the example below. This arrangement of the jet emitting pipes 112 and 113 is such that the-combined effect of the jets will produce what is in effect a flow of operating water rising from the bottom in substantially uniform distribution across the area thereof.

Whereas there has been shown in the foregoing einbodiment of this invention a classifier tank of rectangular or longitudinal shape with the feed entering at one end and the separated fractions leaving at the opposite end, with the horizontal vibration of the bottom portion being in the longitudinal direction of the tank and also codirectional with the horizontal jet emitting pipes, it is to be understood that the construction is not necessarily to b e thus limited. For example, the vibration applied to the tank bottom may be in a direction transversely of the one shown, in which case the jet-emitting pipes may also be disposed to extend co-directional with that direction of vibration; furthermore, the shape of the tank may be other than longitudinal, for example, it may be approximately square; also the disposition of the pulp feed and the discharges of the respective separated fractions may be other than shown, in that, for example, they may be disposed laterally instead of endwise, or the feed may even enter centrally of the classiiier bath, or there may be more than one point of discharge for each fraction. of solids, in that, for example, a fines overflow may be provided at each side of the tank, and similarly a sands discharge be provided: correspondingly at each side.

While there has been shown and described a manner of controlling the density of the classifier pool by way of establishing the super elevation (as defined by the overflow level in the sands receiving chamber), such control may be effected inother suitable ways, for example, by way of measuring or obtaining indications of the density of the classifier pool, and employing them as criteria for adjusting and controlling the rate of a spigot valve` discharge of coarse fraction material from the bottom of the receiving chamber itself. Such manner of control requires eliminating the overilow means from the receiving chamber and it operates to throttle down the coarse fraction discharge means to a suitable extent when the density ofthe pool decreases to below a desired value and to un-throttle the coarse fraction discharge means to` a suitable extent when the density increases to above the desired value.

Automatic means may be provided for effecting such control by applying fluctuations or changes occurring in the density of the pool through suitable relay action in a manner to control the rate of discharge of coarse fraction material from the receiving chamber thus correctively maintaining the desired density in the pool. Such control is to function in the sense that an increase of density in the pool automatically effects a suitable increase in the rate of coarse fraction discharge, whereas a decrease of density automatically effects a suitable decrease in" the rate of coarse fraction discharge. That is to say, density variations in the pool manifest themselves by the fluctuations of a hydraulic column communicating with the pool, which fluctuations are relayed through suitable instrumentation to actuate the coarse fraction discharge means through which the coarse fraction discharges from the receiving chamber, thus to control the rate of coarse fraction discharge in a manner whereby the density in the pool is `kept substantially constant ata desired value for which the automatic control device can be set to function.

A practical example pertaining to the operation of the Figures 1 to 8 embodiment, presents a combination of structural and operational data as follows:

The machine comprises a longitudinal classifying pool about 4 long, about l wide, and about 9" deep, with the sands discharge passage at the bottom being about 1K2 high and the sands discharge weir about S high to be somewhat higher than the sands passage the pool area being 4 square feet. An adjustable edge member may be provided for adjustably varying the height of the sands passage. i

As for the vibrating motion imparted to the bottom of the classifier pool, a practical or suitable operating range for the vibrating stroke underconditions in this example lies in a range of about 1/s to about 1,41, while the stroke frequency covers a practical range of 600 to 1000 reciprocations per minute.

This operating example provides for a stroke length about /l" at a stroke frequency on the order of 700 reciprocations per minute. In this example the hydraulic water is supplied by a pair of longitudinally extending horizontal pipes having a clearance from the bottom of the pool of about l, with center to center spacing between the pipes of about 6", and the center of each pipe in turn spaced a distance of about 3" from the respective side walls of the pool.

In this example, twoijet-emitting pipes are provided parallel to one another each 4 feet long of 1/2 standard pipe, having .622 inside diameters and `.840 outside diameters, with a spacing between the jet holes of 15/16 center to center, the jet holes themselves being drill holes produced with No. 37 drill, andthaving an area each of .00849 square inch, the nominal diameter of the drill hole being .1040 inch, and the total open l it) area of the holes beingl 1.22 square inches for a total number of 144 holes. In this example, the hydraulic water is emitted from the pipes by jets, provided by a double row of jet orifices in each pipe so disposed that a row of jet openings at each side of each pipe would emit jets at an angle of about 20 below the horizontal. Head loss through the holes was 1 foot water column for a flow rate of 18 gallons per minute. The jet emitting pipes extend in the direction of vibration or reciprocation imparted to the bottom of the classification pool.

With a feed of the classifier pool consisting of a deslimed sands mixture having a range of sizes of -20 to -200 Tyler mesh and feeding 79.5 tons per day (dry weight) itis considered that 59.0 ton-s per day (dry weight) pass through the underflow and 20.5 tons per day (dry weight) pass through the overflow; the separation in terms of the size of the cut was 250 microns with a super elevation being maintained at 3% and` a supply of hydraulic operating Water at the rate of 18 gallons per minute.

lt is presumed that these operating data and operating results do not change appreciably if the above specific load of 79.5 tons feed pulp (dry weight) handled by the machine is increased to about double that quantity and even beyond that.

Although the feed pulp in this instance contains 45.2% solids, it was observed that variations in the feed dilution did not materially effect or vary the above operating results, nor do they materially effect the hydraulic water rate required for a certain separation. While the above data apply to a daily throughput of 79.5 tons, the machine is nevertheless rated for a full capacity of 150 tons per day (dry weight) without requiring any material change in the `above operating conditions.

I claim:

l. Apparatus for the hydraulic classification treatment of a pulp containing a mixture of particle sizes ranging from lfine to coarse, to effect the separation of the mixture into a fraction of fines and a fraction of coarse size material, defined as undersize and as oversize particles respectively, which apparatus comprises a classifying pool having said mixture supplied thereto in one portion thereof and said fractions discharged from another portion, said pool proper being confined Within a space defined substantially by a pair of side wall faces, a transverse face at each end, and a horizontal vibratory bottom face, there being provided a solid tank structure having side and end walls as well as a solid bottom constituting said tank structure, an auxiliary bottom member and guide means for horizontally reciprocating said auxiliary bottom within said tank structure, said auxiliary bottom presenting said horizontal vibratory bottom face for the classifier pool, actuating means operatively connected with said auxiliary bottom for imparting thereto said horizontal reciprocatory movement, and sealing means effective between the auxiliary bottom and the surrounding tank structure to discourage the entry of pulp particles into the space between the auxiliary and the solid bottoms, controllable water supply conduit and distributing means disposed at and above said auxiliary bottom for emitting hydraulic auxiliary water at a controlled rate distributively in a manner whereby the water rises in substantially uniform distribution from the bottom, and whereby in turn there are maintainable in said pool horizontal classification zones comprising substantially a sands zone of oversize particles at the bottom, a fines zone of undersize particles at the top, and an intermediate zone containing a mixture of undersize and oversize particles in teeter condition, there being provided an overliow Weir for overflow discharge of undersize particles from said top zone of the pool, and an underflow discharge passage at the bottom, adjustable means for controlling the rate of underflow discharge so that by the concurrent action of the horizontal motion of the bottom face and of the rising flow of the hydraulic water there are producible overow and underow size fractions each substantially free from stray particle sizes of the other.

2. Apparatus according to claim 1, in which the sealing means comprise a body of flexibly deformable and resiliently compressible ller material.

3. Apparatus according to claim l, in which said adjustable control means for sands discharge comprises conning means providing a sands column extending outside said passage, a clear water column of adjustable height superimposed upon said column, and in which there is furthermore provided a receiving chamber communicating with said clear water column to receive sands spilling over from said sands column incident to the operation of the machine.

4. Apparatus according to claim 1 in which said adjustable control means for sands discharge comprises contining means providing a sands column extending outside said passage, a clear water column of adjustable height superimposed upon said sands column; and in which there is furthermore provided a receiving chamber communicating with said clear water column to receive sands spilling over from said sands column incident to the operation of the machine; with the addition of sands removal means comprising a spigot valve provided at the bottom of said receiving chamber.

5. Apparatus according to claim l, in which said adjustable control means for sands discharge comprises confining means providing a sands column extending outside said passage, a clear water column of adjustable height superimposed upon said sands column; in which there is furthermore provided a receiving chamber communicating with said clear Water column to receive sands spilling over from said sands column incident to the operation or" the machine; with the further addition of sands discharge means comprising a sands elevating device to raise sands from the receiving chamber to a point above the clear water level.

6. Apparatus according to claim l, in which said adjustable control means for sands discharge comprises conning means unitary with said solid tank structure bottom, providing a sands column extending outside said passage, a clear water column of adjustable height superimposed upon said sands column; and in which there is furthermore provided a receiving chamber communicating with said clear water column, to receive sands spilling over from said sands column incident to the operation of the machine.

7. Apparatus according to claim 1, in which a wall portion of said tank structure comprises a diaphragm, and said actuating means are operatively connected to said plate through said diaphragm.

8. Apparatus according to claim 1, in which said guide means for the auxiliary bottom member comprise a pair of parallel substantially vertical members for operatively supporting each respective side of the bottom member, each supporting member of each pair having its lower end operatively connected with the bottom member and its upper end operatively connected with the tank.

9. Apparatus for the hydraulic classification treatment of a pulp containing a mixture of particle sizes ranging from fine to coarse, to effect the separation of the mixture into a fraction of finesy and a fraction of coarse size material, deiined as undersize and as oversize particles respectively, which apparatus comprises a classifying pool having said mixture supplied thereto in one portion thereof and said fractions discharged from another portion, said pool proper being confined Within a space defined substantially by a pair of side wall faces, a transverse face at each end, and a horizontal vibratory bottom face, there being provided a solidtank structure having side and end walls as well as a solid bottom constituting said tank structure, an auxiliary bottom member and guide means for horizontally reciprocating i2 said auxiliary bottom within said tank structure, said auxiliary bottom presenting said horizontal vibratory bottom face for the classifier pool, actuating means operatively connected with said auxiliary bottom for imparting thereto said horizontal reciprocatory movement, controllable water supply conduit and distributing means disposed at and above said auxiliary bottom for emitting hydraulic auxiliary water at a controlled krate distributively in a manner whereby the water rises in substan` tially uniform distribution from the bottom, and whereby in turn there are formed and maintained in said pool horizontal classilication zones comprising substantially a sands zone of oversize particles at the bottom, a iines zone of undersize particles at the top, and an intermediate zone containing a mixture of undersize and oversize particles in teeter condition, there being provided an overiiow Weir for overow discharge of undersize particles from said top zone of the pool, and an underflow discharge passage at the bottom, adjustable means for controlling the rate of underilow discharge so that by the concurrent action of the horizontal motion of the bottom face and of the rising ow of the hydraulic water there are producibie overliow and underow size fractions each substantially free from stray particle sizes of the other, and actuating means for imparting horizontal reciprocatory movement to said auxiliary bottom member.

l0. Apparatus according to claim 9, in which said adjustable control means for sands discharge comprises confining means providing a sands column extending outside said passage, a clear water column of adjustable height superimposed upon said column, and in which there is furthermore provided a receiving chamber communicating with said clear water column to receive sands spilling over from said sands column incident to the operation of the machine.

1l. Apparatus according to claim 9, in `vhich said adjustable control means for sands discharge comprises confining means providing a sands column extending outside said passage, a clear water column of adjustable height superimposed upon said sands column; and in which there is furthermore provided a receiving cham` ber communicating with said clear Water column to receive sands spilling over from said sands column incident to the operation of the machine, with the addition of sands removal means comprising a spigot valve provided at the bottom of said receiving chamber.

12. Apparatus according to claim 9, in which said adjustable control means for sands discharge comprises confining means providing a sands column extending outside said passage, a clear water column of adjustable height superimposed upon said sands column; in which there is furthermore provided a receiving chamber communicating with said clear water column to receive sands spilling over from said sands column incident to the operation of the machine; with the further addition of sands discharge means comprising a sands elevating device adapted to raise sands from the receiving chamber to a point above the clear water level.

13. Apparatus according to claim 9, in which said adjustable control means for sands discharge comprises contining means unitary with said solid tank structure bottom, providing a sands column extending outside said passage, a clear Water column of adjustable height superimposed upon said sands column; and in which there is furthermore provided a receiving chamber communieating with said clear Water column, to receive sands spilling over from said sands column incident to the operation of the machine.

14. Apparatus according to claim 9, in which a wall portion of said tank structure comprises a diaphragm, and said actuating means are operatively connected to said plate through said diaphragm.

15. Apparatus according to claim 9, in which said guide means for the auxiliary bottom member comprise member and its upper end operatively connected with 5 the tank.

References Cited in the le of this patent UNITED STATES PATENTS Wall Mar. 27, 1888 Fowler Apr. 19, 1910 Lequeux July 7, 1925 Weber Nov. 17, 1942 

1. APPARATUS FOR THE HYDRAULIC CLASSIFICATION TREATMENT OF A PULP CONTAINING A MIXTURE OF PARTICLE SIZES RANGING FROM FINE TO COARSE, TO EFFECT THE SEPARATION OF THE MIXTURE INTO A FRACTION OF FINES AND A FRACTION OF COARSE SIZE MATERIAL, DEFINED AS UNDERSIZE AND AS OVERSIZE PARTICLES RESPECTIVELY, WHICH APPARATUS COMPRISES A CLASSIFYING POOL HAVING SAID MIXTURE SUPPLIED THERETO IN ONE PORTION THEREOF AND SAID FRACTIONS DISCHARGED FROM ANOTHER PORTION, SAID POOL PROPER BEING CONFINED WITHIN A SPACE DEFINED SUBSTANTIALLY BY A PAIR OF SIDE WALL FACES, A TRANSVERSE FACE AT EACH END, AND A HORIZONTAL VIBRATORY BOTTOM FACE, THERE BEING PROVIDED A SOLID TANK STRUCTURE HAVING SIDE AND END WALLS AS WELL AS A SOLID BOTTOM CONSTITUTING SAID TANK STRUCTURE, AN AUXILIARY BOTTOM MEMBER AND GUIDE MEANS FOR HORIZONTALLY RECIPROCATING SAID AUXILIARY BOTTOM WITHIN SAID TANK STRUCTURE, SAID AUXILIARY BOTTOM PRESENTING SAID HORIZONTAL VIBRATORY BOTTOM FACE FOR THE CLASSIFIER POOL, ACTUATING MEANS OPERATIVELY CONNECTED WITH SAID AUXILIARY BOTTOM FOR IMPARTING THERETO SAID HORIZONTAL RECIPROCATORY MOVEMENT, AND SEALING MEANS EFFECTIVE BETWEEN THE AUXILIARY BOTTOM AND THE SURROUNDING TANK STRUCTURE TO DISCOURAGE THE ENTRY OF PULP PARTICLES INTO THE SPACE BETWEEN THE AUXILIARY AND THE SOLID BOTTOMS, CONTROLLABLE WATER SUPPLY CONDUIT AND DISTRIBUTING MEANS DISPOSED AT AND ABOVE SAID AUXILIARY BOTTOM FOR EMITTING HYDRAULIC AUXILIARY WATER AT A CONTROLLED RATE DISTRIBUTIVELY IN A MANNER WHRERBY THE WATER RISES IN SUBSTANTIALLY UNIFORM DISTRIBUTION FROM THE BOTTOM, AND WHEREBY IN TURN THERE ARE MAINTAINABLE IN SAID POOL HORIZONTAL CLASSIFICATION ZONES COMPRISING SUBSTANTIALLY A SANDS ZONE OF OVERSIZE PARTICLES AT THE BOTTOM, A FINES ZONE OF UNDERSIZE PARTICLES AT THE TOP, AND AN INTERMEDIATE ZONE CONTAINING A MIXTURE OF UNDERSIZE AND OVERSIZE PARTICLES IN TEETER CONDITION, THERE BEING PROVIDED AN OVERFLOW WEIR FOR OVERFLOW DISCHARGE OF UNDERSIZE PARTICLES FROM SAID TOP ZONE OF THE POOL, AND AN UNDERFLOW DISCHARGE PASSAGE AT THE BOTTOM, ADJUSTABLE MEANS FOR CONTROLLING THE RATE OF UNDERFLOW DISCHARGE SO THAT BY THE CONCURRENT ACTION OF THE HORIZONTAL MOTION OF THE BOTTOM FACE AND OF THE RISING FLOW OF THE HYDRAULIC WATER THERE ARE PRODUCIBLE OVERFLFOW AND UNDERFLOW SIZE FRACTIONS EACH SUBSTANTIALLY FREE FROM STRAY PARTICLE SIZES OF THE OTHER. 